/* * INET An implementation of the TCP/IP protocol suite for the LINUX * operating system. INET is implemented using the BSD Socket * interface as the means of communication with the user level. * * The User Datagram Protocol (UDP). * * Version: $Id: udp.c,v 1.102 2002/02/01 22:01:04 davem Exp $ * * Authors: Ross Biro * Fred N. van Kempen, * Arnt Gulbrandsen, * Alan Cox, * Hirokazu Takahashi, * * Fixes: * Alan Cox : verify_area() calls * Alan Cox : stopped close while in use off icmp * messages. Not a fix but a botch that * for udp at least is 'valid'. * Alan Cox : Fixed icmp handling properly * Alan Cox : Correct error for oversized datagrams * Alan Cox : Tidied select() semantics. * Alan Cox : udp_err() fixed properly, also now * select and read wake correctly on errors * Alan Cox : udp_send verify_area moved to avoid mem leak * Alan Cox : UDP can count its memory * Alan Cox : send to an unknown connection causes * an ECONNREFUSED off the icmp, but * does NOT close. * Alan Cox : Switched to new sk_buff handlers. No more backlog! * Alan Cox : Using generic datagram code. Even smaller and the PEEK * bug no longer crashes it. * Fred Van Kempen : Net2e support for sk->broadcast. * Alan Cox : Uses skb_free_datagram * Alan Cox : Added get/set sockopt support. * Alan Cox : Broadcasting without option set returns EACCES. * Alan Cox : No wakeup calls. Instead we now use the callbacks. * Alan Cox : Use ip_tos and ip_ttl * Alan Cox : SNMP Mibs * Alan Cox : MSG_DONTROUTE, and 0.0.0.0 support. * Matt Dillon : UDP length checks. * Alan Cox : Smarter af_inet used properly. * Alan Cox : Use new kernel side addressing. * Alan Cox : Incorrect return on truncated datagram receive. * Arnt Gulbrandsen : New udp_send and stuff * Alan Cox : Cache last socket * Alan Cox : Route cache * Jon Peatfield : Minor efficiency fix to sendto(). * Mike Shaver : RFC1122 checks. * Alan Cox : Nonblocking error fix. * Willy Konynenberg : Transparent proxying support. * Mike McLagan : Routing by source * David S. Miller : New socket lookup architecture. * Last socket cache retained as it * does have a high hit rate. * Olaf Kirch : Don't linearise iovec on sendmsg. * Andi Kleen : Some cleanups, cache destination entry * for connect. * Vitaly E. Lavrov : Transparent proxy revived after year coma. * Melvin Smith : Check msg_name not msg_namelen in sendto(), * return ENOTCONN for unconnected sockets (POSIX) * Janos Farkas : don't deliver multi/broadcasts to a different * bound-to-device socket * Hirokazu Takahashi : HW checksumming for outgoing UDP * datagrams. * Hirokazu Takahashi : sendfile() on UDP works now. * Arnaldo C. Melo : convert /proc/net/udp to seq_file * YOSHIFUJI Hideaki @USAGI and: Support IPV6_V6ONLY socket option, which * Alexey Kuznetsov: allow both IPv4 and IPv6 sockets to bind * a single port at the same time. * Derek Atkins : Add Encapulation Support * James Chapman : Add L2TP encapsulation type. * * * This program is free software; you can redistribute it and/or * modify it under the terms of the GNU General Public License * as published by the Free Software Foundation; either version * 2 of the License, or (at your option) any later version. */ #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include "udp_impl.h" /* * Snmp MIB for the UDP layer */ DEFINE_SNMP_STAT(struct udp_mib, udp_statistics) __read_mostly; struct hlist_head udp_hash[UDP_HTABLE_SIZE]; DEFINE_RWLOCK(udp_hash_lock); static inline int __udp_lib_lport_inuse(__u16 num, const struct hlist_head udptable[]) { struct sock *sk; struct hlist_node *node; sk_for_each(sk, node, &udptable[num & (UDP_HTABLE_SIZE - 1)]) if (sk->sk_hash == num) return 1; return 0; } /** * __udp_lib_get_port - UDP/-Lite port lookup for IPv4 and IPv6 * * @sk: socket struct in question * @snum: port number to look up * @udptable: hash list table, must be of UDP_HTABLE_SIZE * @saddr_comp: AF-dependent comparison of bound local IP addresses */ int __udp_lib_get_port(struct sock *sk, unsigned short snum, struct hlist_head udptable[], int (*saddr_comp)(const struct sock *sk1, const struct sock *sk2 ) ) { struct hlist_node *node; struct hlist_head *head; struct sock *sk2; int error = 1; write_lock_bh(&udp_hash_lock); if (!snum) { int i, low, high, remaining; unsigned rover, best, best_size_so_far; inet_get_local_port_range(&low, &high); remaining = (high - low) + 1; best_size_so_far = UINT_MAX; best = rover = net_random() % remaining + low; /* 1st pass: look for empty (or shortest) hash chain */ for (i = 0; i < UDP_HTABLE_SIZE; i++) { int size = 0; head = &udptable[rover & (UDP_HTABLE_SIZE - 1)]; if (hlist_empty(head)) goto gotit; sk_for_each(sk2, node, head) { if (++size >= best_size_so_far) goto next; } best_size_so_far = size; best = rover; next: /* fold back if end of range */ if (++rover > high) rover = low + ((rover - low) & (UDP_HTABLE_SIZE - 1)); } /* 2nd pass: find hole in shortest hash chain */ rover = best; for (i = 0; i < (1 << 16) / UDP_HTABLE_SIZE; i++) { if (! __udp_lib_lport_inuse(rover, udptable)) goto gotit; rover += UDP_HTABLE_SIZE; if (rover > high) rover = low + ((rover - low) & (UDP_HTABLE_SIZE - 1)); } /* All ports in use! */ goto fail; gotit: snum = rover; } else { head = &udptable[snum & (UDP_HTABLE_SIZE - 1)]; sk_for_each(sk2, node, head) if (sk2->sk_hash == snum && sk2 != sk && (!sk2->sk_reuse || !sk->sk_reuse) && (!sk2->sk_bound_dev_if || !sk->sk_bound_dev_if || sk2->sk_bound_dev_if == sk->sk_bound_dev_if) && (*saddr_comp)(sk, sk2) ) goto fail; } inet_sk(sk)->num = snum; sk->sk_hash = snum; if (sk_unhashed(sk)) { head = &udptable[snum & (UDP_HTABLE_SIZE - 1)]; sk_add_node(sk, head); sock_prot_inc_use(sk->sk_prot); } error = 0; fail: write_unlock_bh(&udp_hash_lock); return error; } int udp_get_port(struct sock *sk, unsigned short snum, int (*scmp)(const struct sock *, const struct sock *)) { return __udp_lib_get_port(sk, snum, udp_hash, scmp); } int ipv4_rcv_saddr_equal(const struct sock *sk1, const struct sock *sk2) { struct inet_sock *inet1 = inet_sk(sk1), *inet2 = inet_sk(sk2); return ( !ipv6_only_sock(sk2) && (!inet1->rcv_saddr || !inet2->rcv_saddr || inet1->rcv_saddr == inet2->rcv_saddr )); } static inline int udp_v4_get_port(struct sock *sk, unsigned short snum) { return udp_get_port(sk, snum, ipv4_rcv_saddr_equal); } /* UDP is nearly always wildcards out the wazoo, it makes no sense to try * harder than this. -DaveM */ static struct sock *__udp4_lib_lookup(__be32 saddr, __be16 sport, __be32 daddr, __be16 dport, int dif, struct hlist_head udptable[]) { struct sock *sk, *result = NULL; struct hlist_node *node; unsigned short hnum = ntohs(dport); int badness = -1; read_lock(&udp_hash_lock); sk_for_each(sk, node, &udptable[hnum & (UDP_HTABLE_SIZE - 1)]) { struct inet_sock *inet = inet_sk(sk); if (sk->sk_hash == hnum && !ipv6_only_sock(sk)) { int score = (sk->sk_family == PF_INET ? 1 : 0); if (inet->rcv_saddr) { if (inet->rcv_saddr != daddr) continue; score+=2; } if (inet->daddr) { if (inet->daddr != saddr) continue; score+=2; } if (inet->dport) { if (inet->dport != sport) continue; score+=2; } if (sk->sk_bound_dev_if) { if (sk->sk_bound_dev_if != dif) continue; score+=2; } if (score == 9) { result = sk; break; } else if (score > badness) { result = sk; badness = score; } } } if (result) sock_hold(result); read_unlock(&udp_hash_lock); return result; } static inline struct sock *udp_v4_mcast_next(struct sock *sk, __be16 loc_port, __be32 loc_addr, __be16 rmt_port, __be32 rmt_addr, int dif) { struct hlist_node *node; struct sock *s = sk; unsigned short hnum = ntohs(loc_port); sk_for_each_from(s, node) { struct inet_sock *inet = inet_sk(s); if (s->sk_hash != hnum || (inet->daddr && inet->daddr != rmt_addr) || (inet->dport != rmt_port && inet->dport) || (inet->rcv_saddr && inet->rcv_saddr != loc_addr) || ipv6_only_sock(s) || (s->sk_bound_dev_if && s->sk_bound_dev_if != dif)) continue; if (!ip_mc_sf_allow(s, loc_addr, rmt_addr, dif)) continue; goto found; } s = NULL; found: return s; } /* * This routine is called by the ICMP module when it gets some * sort of error condition. If err < 0 then the socket should * be closed and the error returned to the user. If err > 0 * it's just the icmp type << 8 | icmp code. * Header points to the ip header of the error packet. We move * on past this. Then (as it used to claim before adjustment) * header points to the first 8 bytes of the udp header. We need * to find the appropriate port. */ void __udp4_lib_err(struct sk_buff *skb, u32 info, struct hlist_head udptable[]) { struct inet_sock *inet; struct iphdr *iph = (struct iphdr*)skb->data; struct udphdr *uh = (struct udphdr*)(skb->data+(iph->ihl<<2)); const int type = icmp_hdr(skb)->type; const int code = icmp_hdr(skb)->code; struct sock *sk; int harderr; int err; sk = __udp4_lib_lookup(iph->daddr, uh->dest, iph->saddr, uh->source, skb->dev->ifindex, udptable ); if (sk == NULL) { ICMP_INC_STATS_BH(ICMP_MIB_INERRORS); return; /* No socket for error */ } err = 0; harderr = 0; inet = inet_sk(sk); switch (type) { default: case ICMP_TIME_EXCEEDED: err = EHOSTUNREACH; break; case ICMP_SOURCE_QUENCH: goto out; case ICMP_PARAMETERPROB: err = EPROTO; harderr = 1; break; case ICMP_DEST_UNREACH: if (code == ICMP_FRAG_NEEDED) { /* Path MTU discovery */ if (inet->pmtudisc != IP_PMTUDISC_DONT) { err = EMSGSIZE; harderr = 1; break; } goto out; } err = EHOSTUNREACH; if (code <= NR_ICMP_UNREACH) { harderr = icmp_err_convert[code].fatal; err = icmp_err_convert[code].errno; } break; } /* * RFC1122: OK. Passes ICMP errors back to application, as per * 4.1.3.3. */ if (!inet->recverr) { if (!harderr || sk->sk_state != TCP_ESTABLISHED) goto out; } else { ip_icmp_error(sk, skb, err, uh->dest, info, (u8*)(uh+1)); } sk->sk_err = err; sk->sk_error_report(sk); out: sock_put(sk); } void udp_err(struct sk_buff *skb, u32 info) { return __udp4_lib_err(skb, info, udp_hash); } /* * Throw away all pending data and cancel the corking. Socket is locked. */ static void udp_flush_pending_frames(struct sock *sk) { struct udp_sock *up = udp_sk(sk); if (up->pending) { up->len = 0; up->pending = 0; ip_flush_pending_frames(sk); } } /** * udp4_hwcsum_outgoing - handle outgoing HW checksumming * @sk: socket we are sending on * @skb: sk_buff containing the filled-in UDP header * (checksum field must be zeroed out) */ static void udp4_hwcsum_outgoing(struct sock *sk, struct sk_buff *skb, __be32 src, __be32 dst, int len ) { unsigned int offset; struct udphdr *uh = udp_hdr(skb); __wsum csum = 0; if (skb_queue_len(&sk->sk_write_queue) == 1) { /* * Only one fragment on the socket. */ skb->csum_start = skb_transport_header(skb) - skb->head; skb->csum_offset = offsetof(struct udphdr, check); uh->check = ~csum_tcpudp_magic(src, dst, len, IPPROTO_UDP, 0); } else { /* * HW-checksum won't work as there are two or more * fragments on the socket so that all csums of sk_buffs * should be together */ offset = skb_transport_offset(skb); skb->csum = skb_checksum(skb, offset, skb->len - offset, 0); skb->ip_summed = CHECKSUM_NONE; skb_queue_walk(&sk->sk_write_queue, skb) { csum = csum_add(csum, skb->csum); } uh->check = csum_tcpudp_magic(src, dst, len, IPPROTO_UDP, csum); if (uh->check == 0) uh->check = CSUM_MANGLED_0; } } /* * Push out all pending data as one UDP datagram. Socket is locked. */ static int udp_push_pending_frames(struct sock *sk) { struct udp_sock *up = udp_sk(sk); struct inet_sock *inet = inet_sk(sk); struct flowi *fl = &inet->cork.fl; struct sk_buff *skb; struct udphdr *uh; int err = 0; __wsum csum = 0; /* Grab the skbuff where UDP header space exists. */ if ((skb = skb_peek(&sk->sk_write_queue)) == NULL) goto out; /* * Create a UDP header */ uh = udp_hdr(skb); uh->source = fl->fl_ip_sport; uh->dest = fl->fl_ip_dport; uh->len = htons(up->len); uh->check = 0; if (up->pcflag) /* UDP-Lite */ csum = udplite_csum_outgoing(sk, skb); else if (sk->sk_no_check == UDP_CSUM_NOXMIT) { /* UDP csum disabled */ skb->ip_summed = CHECKSUM_NONE; goto send; } else if (skb->ip_summed == CHECKSUM_PARTIAL) { /* UDP hardware csum */ udp4_hwcsum_outgoing(sk, skb, fl->fl4_src,fl->fl4_dst, up->len); goto send; } else /* `normal' UDP */ csum = udp_csum_outgoing(sk, skb); /* add protocol-dependent pseudo-header */ uh->check = csum_tcpudp_magic(fl->fl4_src, fl->fl4_dst, up->len, sk->sk_protocol, csum ); if (uh->check == 0) uh->check = CSUM_MANGLED_0; send: err = ip_push_pending_frames(sk); out: up->len = 0; up->pending = 0; if (!err) UDP_INC_STATS_USER(UDP_MIB_OUTDATAGRAMS, up->pcflag); return err; } int udp_sendmsg(struct kiocb *iocb, struct sock *sk, struct msghdr *msg, size_t len) { struct inet_sock *inet = inet_sk(sk); struct udp_sock *up = udp_sk(sk); int ulen = len; struct ipcm_cookie ipc; struct rtable *rt = NULL; int free = 0; int connected = 0; __be32 daddr, faddr, saddr; __be16 dport; u8 tos; int err, is_udplite = up->pcflag; int corkreq = up->corkflag || msg->msg_flags&MSG_MORE; int (*getfrag)(void *, char *, int, int, int, struct sk_buff *); if (len > 0xFFFF) return -EMSGSIZE; /* * Check the flags. */ if (msg->msg_flags&MSG_OOB) /* Mirror BSD error message compatibility */ return -EOPNOTSUPP; ipc.opt = NULL; if (up->pending) { /* * There are pending frames. * The socket lock must be held while it's corked. */ lock_sock(sk); if (likely(up->pending)) { if (unlikely(up->pending != AF_INET)) { release_sock(sk); return -EINVAL; } goto do_append_data; } release_sock(sk); } ulen += sizeof(struct udphdr); /* * Get and verify the address. */ if (msg->msg_name) { struct sockaddr_in * usin = (struct sockaddr_in*)msg->msg_name; if (msg->msg_namelen < sizeof(*usin)) return -EINVAL; if (usin->sin_family != AF_INET) { if (usin->sin_family != AF_UNSPEC) return -EAFNOSUPPORT; } daddr = usin->sin_addr.s_addr; dport = usin->sin_port; if (dport == 0) return -EINVAL; } else { if (sk->sk_state != TCP_ESTABLISHED) return -EDESTADDRREQ; daddr = inet->daddr; dport = inet->dport; /* Open fast path for connected socket. Route will not be used, if at least one option is set. */ connected = 1; } ipc.addr = inet->saddr; ipc.oif = sk->sk_bound_dev_if; if (msg->msg_controllen) { err = ip_cmsg_send(msg, &ipc); if (err) return err; if (ipc.opt) free = 1; connected = 0; } if (!ipc.opt) ipc.opt = inet->opt; saddr = ipc.addr; ipc.addr = faddr = daddr; if (ipc.opt && ipc.opt->srr) { if (!daddr) return -EINVAL; faddr = ipc.opt->faddr; connected = 0; } tos = RT_TOS(inet->tos); if (sock_flag(sk, SOCK_LOCALROUTE) || (msg->msg_flags & MSG_DONTROUTE) || (ipc.opt && ipc.opt->is_strictroute)) { tos |= RTO_ONLINK; connected = 0; } if (MULTICAST(daddr)) { if (!ipc.oif) ipc.oif = inet->mc_index; if (!saddr) saddr = inet->mc_addr; connected = 0; } if (connected) rt = (struct rtable*)sk_dst_check(sk, 0); if (rt == NULL) { struct flowi fl = { .oif = ipc.oif, .nl_u = { .ip4_u = { .daddr = faddr, .saddr = saddr, .tos = tos } }, .proto = sk->sk_protocol, .uli_u = { .ports = { .sport = inet->sport, .dport = dport } } }; security_sk_classify_flow(sk, &fl); err = ip_route_output_flow(&rt, &fl, sk, 1); if (err) { if (err == -ENETUNREACH) IP_INC_STATS_BH(IPSTATS_MIB_OUTNOROUTES); goto out; } err = -EACCES; if ((rt->rt_flags & RTCF_BROADCAST) && !sock_flag(sk, SOCK_BROADCAST)) goto out; if (connected) sk_dst_set(sk, dst_clone(&rt->u.dst)); } if (msg->msg_flags&MSG_CONFIRM) goto do_confirm; back_from_confirm: saddr = rt->rt_src; if (!ipc.addr) daddr = ipc.addr = rt->rt_dst; lock_sock(sk); if (unlikely(up->pending)) { /* The socket is already corked while preparing it. */ /* ... which is an evident application bug. --ANK */ release_sock(sk); LIMIT_NETDEBUG(KERN_DEBUG "udp cork app bug 2\n"); err = -EINVAL; goto out; } /* * Now cork the socket to pend data. */ inet->cork.fl.fl4_dst = daddr; inet->cork.fl.fl_ip_dport = dport; inet->cork.fl.fl4_src = saddr; inet->cork.fl.fl_ip_sport = inet->sport; up->pending = AF_INET; do_append_data: up->len += ulen; getfrag = is_udplite ? udplite_getfrag : ip_generic_getfrag; err = ip_append_data(sk, getfrag, msg->msg_iov, ulen, sizeof(struct udphdr), &ipc, rt, corkreq ? msg->msg_flags|MSG_MORE : msg->msg_flags); if (err) udp_flush_pending_frames(sk); else if (!corkreq) err = udp_push_pending_frames(sk); else if (unlikely(skb_queue_empty(&sk->sk_write_queue))) up->pending = 0; release_sock(sk); out: ip_rt_put(rt); if (free) kfree(ipc.opt); if (!err) return len; /* * ENOBUFS = no kernel mem, SOCK_NOSPACE = no sndbuf space. Reporting * ENOBUFS might not be good (it's not tunable per se), but otherwise * we don't have a good statistic (IpOutDiscards but it can be too many * things). We could add another new stat but at least for now that * seems like overkill. */ if (err == -ENOBUFS || test_bit(SOCK_NOSPACE, &sk->sk_socket->flags)) { UDP_INC_STATS_USER(UDP_MIB_SNDBUFERRORS, is_udplite); } return err; do_confirm: dst_confirm(&rt->u.dst); if (!(msg->msg_flags&MSG_PROBE) || len) goto back_from_confirm; err = 0; goto out; } int udp_sendpage(struct sock *sk, struct page *page, int offset, size_t size, int flags) { struct udp_sock *up = udp_sk(sk); int ret; if (!up->pending) { struct msghdr msg = { .msg_flags = flags|MSG_MORE }; /* Call udp_sendmsg to specify destination address which * sendpage interface can't pass. * This will succeed only when the socket is connected. */ ret = udp_sendmsg(NULL, sk, &msg, 0); if (ret < 0) return ret; } lock_sock(sk); if (unlikely(!up->pending)) { release_sock(sk); LIMIT_NETDEBUG(KERN_DEBUG "udp cork app bug 3\n"); return -EINVAL; } ret = ip_append_page(sk, page, offset, size, flags); if (ret == -EOPNOTSUPP) { release_sock(sk); return sock_no_sendpage(sk->sk_socket, page, offset, size, flags); } if (ret < 0) { udp_flush_pending_frames(sk); goto out; } up->len += size; if (!(up->corkflag || (flags&MSG_MORE))) ret = udp_push_pending_frames(sk); if (!ret) ret = size; out: release_sock(sk); return ret; } /* * IOCTL requests applicable to the UDP protocol */ int udp_ioctl(struct sock *sk, int cmd, unsigned long arg) { switch (cmd) { case SIOCOUTQ: { int amount = atomic_read(&sk->sk_wmem_alloc); return put_user(amount, (int __user *)arg); } case SIOCINQ: { struct sk_buff *skb; unsigned long amount; amount = 0; spin_lock_bh(&sk->sk_receive_queue.lock); skb = skb_peek(&sk->sk_receive_queue); if (skb != NULL) { /* * We will only return the amount * of this packet since that is all * that will be read. */ amount = skb->len - sizeof(struct udphdr); } spin_unlock_bh(&sk->sk_receive_queue.lock); return put_user(amount, (int __user *)arg); } default: return -ENOIOCTLCMD; } return 0; } /* * This should be easy, if there is something there we * return it, otherwise we block. */ int udp_recvmsg(struct kiocb *iocb, struct sock *sk, struct msghdr *msg, size_t len, int noblock, int flags, int *addr_len) { struct inet_sock *inet = inet_sk(sk); struct sockaddr_in *sin = (struct sockaddr_in *)msg->msg_name; struct sk_buff *skb; unsigned int ulen, copied; int err; int is_udplite = IS_UDPLITE(sk); /* * Check any passed addresses */ if (addr_len) *addr_len=sizeof(*sin); if (flags & MSG_ERRQUEUE) return ip_recv_error(sk, msg, len); try_again: skb = skb_recv_datagram(sk, flags, noblock, &err); if (!skb) goto out; ulen = skb->len - sizeof(struct udphdr); copied = len; if (copied > ulen) copied = ulen; else if (copied < ulen) msg->msg_flags |= MSG_TRUNC; /* * If checksum is needed at all, try to do it while copying the * data. If the data is truncated, or if we only want a partial * coverage checksum (UDP-Lite), do it before the copy. */ if (copied < ulen || UDP_SKB_CB(skb)->partial_cov) { if (udp_lib_checksum_complete(skb)) goto csum_copy_err; } if (skb_csum_unnecessary(skb)) err = skb_copy_datagram_iovec(skb, sizeof(struct udphdr), msg->msg_iov, copied ); else { err = skb_copy_and_csum_datagram_iovec(skb, sizeof(struct udphdr), msg->msg_iov); if (err == -EINVAL) goto csum_copy_err; } if (err) goto out_free; sock_recv_timestamp(msg, sk, skb); /* Copy the address. */ if (sin) { sin->sin_family = AF_INET; sin->sin_port = udp_hdr(skb)->source; sin->sin_addr.s_addr = ip_hdr(skb)->saddr; memset(sin->sin_zero, 0, sizeof(sin->sin_zero)); } if (inet->cmsg_flags) ip_cmsg_recv(msg, skb); err = copied; if (flags & MSG_TRUNC) err = ulen; out_free: skb_free_datagram(sk, skb); out: return err; csum_copy_err: UDP_INC_STATS_BH(UDP_MIB_INERRORS, is_udplite); skb_kill_datagram(sk, skb, flags); if (noblock) return -EAGAIN; goto try_again; } int udp_disconnect(struct sock *sk, int flags) { struct inet_sock *inet = inet_sk(sk); /* * 1003.1g - break association. */ sk->sk_state = TCP_CLOSE; inet->daddr = 0; inet->dport = 0; sk->sk_bound_dev_if = 0; if (!(sk->sk_userlocks & SOCK_BINDADDR_LOCK)) inet_reset_saddr(sk); if (!(sk->sk_userlocks & SOCK_BINDPORT_LOCK)) { sk->sk_prot->unhash(sk); inet->sport = 0; } sk_dst_reset(sk); return 0; } /* returns: * -1: error * 0: success * >0: "udp encap" protocol resubmission * * Note that in the success and error cases, the skb is assumed to * have either been requeued or freed. */ int udp_queue_rcv_skb(struct sock * sk, struct sk_buff *skb) { struct udp_sock *up = udp_sk(sk); int rc; /* * Charge it to the socket, dropping if the queue is full. */ if (!xfrm4_policy_check(sk, XFRM_POLICY_IN, skb)) goto drop; nf_reset(skb); if (up->encap_type) { /* * This is an encapsulation socket so pass the skb to * the socket's udp_encap_rcv() hook. Otherwise, just * fall through and pass this up the UDP socket. * up->encap_rcv() returns the following value: * =0 if skb was successfully passed to the encap * handler or was discarded by it. * >0 if skb should be passed on to UDP. * <0 if skb should be resubmitted as proto -N */ /* if we're overly short, let UDP handle it */ if (skb->len > sizeof(struct udphdr) && up->encap_rcv != NULL) { int ret; ret = (*up->encap_rcv)(sk, skb); if (ret <= 0) { UDP_INC_STATS_BH(UDP_MIB_INDATAGRAMS, up->pcflag); return -ret; } } /* FALLTHROUGH -- it's a UDP Packet */ } /* * UDP-Lite specific tests, ignored on UDP sockets */ if ((up->pcflag & UDPLITE_RECV_CC) && UDP_SKB_CB(skb)->partial_cov) { /* * MIB statistics other than incrementing the error count are * disabled for the following two types of errors: these depend * on the application settings, not on the functioning of the * protocol stack as such. * * RFC 3828 here recommends (sec 3.3): "There should also be a * way ... to ... at least let the receiving application block * delivery of packets with coverage values less than a value * provided by the application." */ if (up->pcrlen == 0) { /* full coverage was set */ LIMIT_NETDEBUG(KERN_WARNING "UDPLITE: partial coverage " "%d while full coverage %d requested\n", UDP_SKB_CB(skb)->cscov, skb->len); goto drop; } /* The next case involves violating the min. coverage requested * by the receiver. This is subtle: if receiver wants x and x is * greater than the buffersize/MTU then receiver will complain * that it wants x while sender emits packets of smaller size y. * Therefore the above ...()->partial_cov statement is essential. */ if (UDP_SKB_CB(skb)->cscov < up->pcrlen) { LIMIT_NETDEBUG(KERN_WARNING "UDPLITE: coverage %d too small, need min %d\n", UDP_SKB_CB(skb)->cscov, up->pcrlen); goto drop; } } if (sk->sk_filter) { if (udp_lib_checksum_complete(skb)) goto drop; } if ((rc = sock_queue_rcv_skb(sk,skb)) < 0) { /* Note that an ENOMEM error is charged twice */ if (rc == -ENOMEM) UDP_INC_STATS_BH(UDP_MIB_RCVBUFERRORS, up->pcflag); goto drop; } UDP_INC_STATS_BH(UDP_MIB_INDATAGRAMS, up->pcflag); return 0; drop: UDP_INC_STATS_BH(UDP_MIB_INERRORS, up->pcflag); kfree_skb(skb); return -1; } /* * Multicasts and broadcasts go to each listener. * * Note: called only from the BH handler context, * so we don't need to lock the hashes. */ static int __udp4_lib_mcast_deliver(struct sk_buff *skb, struct udphdr *uh, __be32 saddr, __be32 daddr, struct hlist_head udptable[]) { struct sock *sk; int dif; read_lock(&udp_hash_lock); sk = sk_head(&udptable[ntohs(uh->dest) & (UDP_HTABLE_SIZE - 1)]); dif = skb->dev->ifindex; sk = udp_v4_mcast_next(sk, uh->dest, daddr, uh->source, saddr, dif); if (sk) { struct sock *sknext = NULL; do { struct sk_buff *skb1 = skb; sknext = udp_v4_mcast_next(sk_next(sk), uh->dest, daddr, uh->source, saddr, dif); if (sknext) skb1 = skb_clone(skb, GFP_ATOMIC); if (skb1) { int ret = udp_queue_rcv_skb(sk, skb1); if (ret > 0) /* we should probably re-process instead * of dropping packets here. */ kfree_skb(skb1); } sk = sknext; } while (sknext); } else kfree_skb(skb); read_unlock(&udp_hash_lock); return 0; } /* Initialize UDP checksum. If exited with zero value (success), * CHECKSUM_UNNECESSARY means, that no more checks are required. * Otherwise, csum completion requires chacksumming packet body, * including udp header and folding it to skb->csum. */ static inline int udp4_csum_init(struct sk_buff *skb, struct udphdr *uh, int proto) { const struct iphdr *iph; int err; UDP_SKB_CB(skb)->partial_cov = 0; UDP_SKB_CB(skb)->cscov = skb->len; if (proto == IPPROTO_UDPLITE) { err = udplite_checksum_init(skb, uh); if (err) return err; } iph = ip_hdr(skb); if (uh->check == 0) { skb->ip_summed = CHECKSUM_UNNECESSARY; } else if (skb->ip_summed == CHECKSUM_COMPLETE) { if (!csum_tcpudp_magic(iph->saddr, iph->daddr, skb->len, proto, skb->csum)) skb->ip_summed = CHECKSUM_UNNECESSARY; } if (!skb_csum_unnecessary(skb)) skb->csum = csum_tcpudp_nofold(iph->saddr, iph->daddr, skb->len, proto, 0); /* Probably, we should checksum udp header (it should be in cache * in any case) and data in tiny packets (< rx copybreak). */ return 0; } /* * All we need to do is get the socket, and then do a checksum. */ int __udp4_lib_rcv(struct sk_buff *skb, struct hlist_head udptable[], int proto) { struct sock *sk; struct udphdr *uh = udp_hdr(skb); unsigned short ulen; struct rtable *rt = (struct rtable*)skb->dst; __be32 saddr = ip_hdr(skb)->saddr; __be32 daddr = ip_hdr(skb)->daddr; /* * Validate the packet. */ if (!pskb_may_pull(skb, sizeof(struct udphdr))) goto drop; /* No space for header. */ ulen = ntohs(uh->len); if (ulen > skb->len) goto short_packet; if (proto == IPPROTO_UDP) { /* UDP validates ulen. */ if (ulen < sizeof(*uh) || pskb_trim_rcsum(skb, ulen)) goto short_packet; uh = udp_hdr(skb); } if (udp4_csum_init(skb, uh, proto)) goto csum_error; if (rt->rt_flags & (RTCF_BROADCAST|RTCF_MULTICAST)) return __udp4_lib_mcast_deliver(skb, uh, saddr, daddr, udptable); sk = __udp4_lib_lookup(saddr, uh->source, daddr, uh->dest, inet_iif(skb), udptable); if (sk != NULL) { int ret = udp_queue_rcv_skb(sk, skb); sock_put(sk); /* a return value > 0 means to resubmit the input, but * it wants the return to be -protocol, or 0 */ if (ret > 0) return -ret; return 0; } if (!xfrm4_policy_check(NULL, XFRM_POLICY_IN, skb)) goto drop; nf_reset(skb); /* No socket. Drop packet silently, if checksum is wrong */ if (udp_lib_checksum_complete(skb)) goto csum_error; UDP_INC_STATS_BH(UDP_MIB_NOPORTS, proto == IPPROTO_UDPLITE); icmp_send(skb, ICMP_DEST_UNREACH, ICMP_PORT_UNREACH, 0); /* * Hmm. We got an UDP packet to a port to which we * don't wanna listen. Ignore it. */ kfree_skb(skb); return 0; short_packet: LIMIT_NETDEBUG(KERN_DEBUG "UDP%s: short packet: From %u.%u.%u.%u:%u %d/%d to %u.%u.%u.%u:%u\n", proto == IPPROTO_UDPLITE ? "-Lite" : "", NIPQUAD(saddr), ntohs(uh->source), ulen, skb->len, NIPQUAD(daddr), ntohs(uh->dest)); goto drop; csum_error: /* * RFC1122: OK. Discards the bad packet silently (as far as * the network is concerned, anyway) as per 4.1.3.4 (MUST). */ LIMIT_NETDEBUG(KERN_DEBUG "UDP%s: bad checksum. From %d.%d.%d.%d:%d to %d.%d.%d.%d:%d ulen %d\n", proto == IPPROTO_UDPLITE ? "-Lite" : "", NIPQUAD(saddr), ntohs(uh->source), NIPQUAD(daddr), ntohs(uh->dest), ulen); drop: UDP_INC_STATS_BH(UDP_MIB_INERRORS, proto == IPPROTO_UDPLITE); kfree_skb(skb); return 0; } int udp_rcv(struct sk_buff *skb) { return __udp4_lib_rcv(skb, udp_hash, IPPROTO_UDP); } int udp_destroy_sock(struct sock *sk) { lock_sock(sk); udp_flush_pending_frames(sk); release_sock(sk); return 0; } /* * Socket option code for UDP */ int udp_lib_setsockopt(struct sock *sk, int level, int optname, char __user *optval, int optlen, int (*push_pending_frames)(struct sock *)) { struct udp_sock *up = udp_sk(sk); int val; int err = 0; if (optlencorkflag = 1; } else { up->corkflag = 0; lock_sock(sk); (*push_pending_frames)(sk); release_sock(sk); } break; case UDP_ENCAP: switch (val) { case 0: case UDP_ENCAP_ESPINUDP: case UDP_ENCAP_ESPINUDP_NON_IKE: up->encap_rcv = xfrm4_udp_encap_rcv; /* FALLTHROUGH */ case UDP_ENCAP_L2TPINUDP: up->encap_type = val; break; default: err = -ENOPROTOOPT; break; } break; /* * UDP-Lite's partial checksum coverage (RFC 3828). */ /* The sender sets actual checksum coverage length via this option. * The case coverage > packet length is handled by send module. */ case UDPLITE_SEND_CSCOV: if (!up->pcflag) /* Disable the option on UDP sockets */ return -ENOPROTOOPT; if (val != 0 && val < 8) /* Illegal coverage: use default (8) */ val = 8; up->pcslen = val; up->pcflag |= UDPLITE_SEND_CC; break; /* The receiver specifies a minimum checksum coverage value. To make * sense, this should be set to at least 8 (as done below). If zero is * used, this again means full checksum coverage. */ case UDPLITE_RECV_CSCOV: if (!up->pcflag) /* Disable the option on UDP sockets */ return -ENOPROTOOPT; if (val != 0 && val < 8) /* Avoid silly minimal values. */ val = 8; up->pcrlen = val; up->pcflag |= UDPLITE_RECV_CC; break; default: err = -ENOPROTOOPT; break; } return err; } int udp_setsockopt(struct sock *sk, int level, int optname, char __user *optval, int optlen) { if (level == SOL_UDP || level == SOL_UDPLITE) return udp_lib_setsockopt(sk, level, optname, optval, optlen, udp_push_pending_frames); return ip_setsockopt(sk, level, optname, optval, optlen); } #ifdef CONFIG_COMPAT int compat_udp_setsockopt(struct sock *sk, int level, int optname, char __user *optval, int optlen) { if (level == SOL_UDP || level == SOL_UDPLITE) return udp_lib_setsockopt(sk, level, optname, optval, optlen, udp_push_pending_frames); return compat_ip_setsockopt(sk, level, optname, optval, optlen); } #endif int udp_lib_getsockopt(struct sock *sk, int level, int optname, char __user *optval, int __user *optlen) { struct udp_sock *up = udp_sk(sk); int val, len; if (get_user(len,optlen)) return -EFAULT; len = min_t(unsigned int, len, sizeof(int)); if (len < 0) return -EINVAL; switch (optname) { case UDP_CORK: val = up->corkflag; break; case UDP_ENCAP: val = up->encap_type; break; /* The following two cannot be changed on UDP sockets, the return is * always 0 (which corresponds to the full checksum coverage of UDP). */ case UDPLITE_SEND_CSCOV: val = up->pcslen; break; case UDPLITE_RECV_CSCOV: val = up->pcrlen; break; default: return -ENOPROTOOPT; } if (put_user(len, optlen)) return -EFAULT; if (copy_to_user(optval, &val,len)) return -EFAULT; return 0; } int udp_getsockopt(struct sock *sk, int level, int optname, char __user *optval, int __user *optlen) { if (level == SOL_UDP || level == SOL_UDPLITE) return udp_lib_getsockopt(sk, level, optname, optval, optlen); return ip_getsockopt(sk, level, optname, optval, optlen); } #ifdef CONFIG_COMPAT int compat_udp_getsockopt(struct sock *sk, int level, int optname, char __user *optval, int __user *optlen) { if (level == SOL_UDP || level == SOL_UDPLITE) return udp_lib_getsockopt(sk, level, optname, optval, optlen); return compat_ip_getsockopt(sk, level, optname, optval, optlen); } #endif /** * udp_poll - wait for a UDP event. * @file - file struct * @sock - socket * @wait - poll table * * This is same as datagram poll, except for the special case of * blocking sockets. If application is using a blocking fd * and a packet with checksum error is in the queue; * then it could get return from select indicating data available * but then block when reading it. Add special case code * to work around these arguably broken applications. */ unsigned int udp_poll(struct file *file, struct socket *sock, poll_table *wait) { unsigned int mask = datagram_poll(file, sock, wait); struct sock *sk = sock->sk; int is_lite = IS_UDPLITE(sk); /* Check for false positives due to checksum errors */ if ( (mask & POLLRDNORM) && !(file->f_flags & O_NONBLOCK) && !(sk->sk_shutdown & RCV_SHUTDOWN)){ struct sk_buff_head *rcvq = &sk->sk_receive_queue; struct sk_buff *skb; spin_lock_bh(&rcvq->lock); while ((skb = skb_peek(rcvq)) != NULL && udp_lib_checksum_complete(skb)) { UDP_INC_STATS_BH(UDP_MIB_INERRORS, is_lite); __skb_unlink(skb, rcvq); kfree_skb(skb); } spin_unlock_bh(&rcvq->lock); /* nothing to see, move along */ if (skb == NULL) mask &= ~(POLLIN | POLLRDNORM); } return mask; } struct proto udp_prot = { .name = "UDP", .owner = THIS_MODULE, .close = udp_lib_close, .connect = ip4_datagram_connect, .disconnect = udp_disconnect, .ioctl = udp_ioctl, .destroy = udp_destroy_sock, .setsockopt = udp_setsockopt, .getsockopt = udp_getsockopt, .sendmsg = udp_sendmsg, .recvmsg = udp_recvmsg, .sendpage = udp_sendpage, .backlog_rcv = udp_queue_rcv_skb, .hash = udp_lib_hash, .unhash = udp_lib_unhash, .get_port = udp_v4_get_port, .obj_size = sizeof(struct udp_sock), #ifdef CONFIG_COMPAT .compat_setsockopt = compat_udp_setsockopt, .compat_getsockopt = compat_udp_getsockopt, #endif }; /* ------------------------------------------------------------------------ */ #ifdef CONFIG_PROC_FS static struct sock *udp_get_first(struct seq_file *seq) { struct sock *sk; struct udp_iter_state *state = seq->private; for (state->bucket = 0; state->bucket < UDP_HTABLE_SIZE; ++state->bucket) { struct hlist_node *node; sk_for_each(sk, node, state->hashtable + state->bucket) { if (sk->sk_family == state->family) goto found; } } sk = NULL; found: return sk; } static struct sock *udp_get_next(struct seq_file *seq, struct sock *sk) { struct udp_iter_state *state = seq->private; do { sk = sk_next(sk); try_again: ; } while (sk && sk->sk_family != state->family); if (!sk && ++state->bucket < UDP_HTABLE_SIZE) { sk = sk_head(state->hashtable + state->bucket); goto try_again; } return sk; } static struct sock *udp_get_idx(struct seq_file *seq, loff_t pos) { struct sock *sk = udp_get_first(seq); if (sk) while (pos && (sk = udp_get_next(seq, sk)) != NULL) --pos; return pos ? NULL : sk; } static void *udp_seq_start(struct seq_file *seq, loff_t *pos) { read_lock(&udp_hash_lock); return *pos ? udp_get_idx(seq, *pos-1) : (void *)1; } static void *udp_seq_next(struct seq_file *seq, void *v, loff_t *pos) { struct sock *sk; if (v == (void *)1) sk = udp_get_idx(seq, 0); else sk = udp_get_next(seq, v); ++*pos; return sk; } static void udp_seq_stop(struct seq_file *seq, void *v) { read_unlock(&udp_hash_lock); } static int udp_seq_open(struct inode *inode, struct file *file) { struct udp_seq_afinfo *afinfo = PDE(inode)->data; struct seq_file *seq; int rc = -ENOMEM; struct udp_iter_state *s = kzalloc(sizeof(*s), GFP_KERNEL); if (!s) goto out; s->family = afinfo->family; s->hashtable = afinfo->hashtable; s->seq_ops.start = udp_seq_start; s->seq_ops.next = udp_seq_next; s->seq_ops.show = afinfo->seq_show; s->seq_ops.stop = udp_seq_stop; rc = seq_open(file, &s->seq_ops); if (rc) goto out_kfree; seq = file->private_data; seq->private = s; out: return rc; out_kfree: kfree(s); goto out; } /* ------------------------------------------------------------------------ */ int udp_proc_register(struct udp_seq_afinfo *afinfo) { struct proc_dir_entry *p; int rc = 0; if (!afinfo) return -EINVAL; afinfo->seq_fops->owner = afinfo->owner; afinfo->seq_fops->open = udp_seq_open; afinfo->seq_fops->read = seq_read; afinfo->seq_fops->llseek = seq_lseek; afinfo->seq_fops->release = seq_release_private; p = proc_net_fops_create(&init_net, afinfo->name, S_IRUGO, afinfo->seq_fops); if (p) p->data = afinfo; else rc = -ENOMEM; return rc; } void udp_proc_unregister(struct udp_seq_afinfo *afinfo) { if (!afinfo) return; proc_net_remove(&init_net, afinfo->name); memset(afinfo->seq_fops, 0, sizeof(*afinfo->seq_fops)); } /* ------------------------------------------------------------------------ */ static void udp4_format_sock(struct sock *sp, char *tmpbuf, int bucket) { struct inet_sock *inet = inet_sk(sp); __be32 dest = inet->daddr; __be32 src = inet->rcv_saddr; __u16 destp = ntohs(inet->dport); __u16 srcp = ntohs(inet->sport); sprintf(tmpbuf, "%4d: %08X:%04X %08X:%04X" " %02X %08X:%08X %02X:%08lX %08X %5d %8d %lu %d %p", bucket, src, srcp, dest, destp, sp->sk_state, atomic_read(&sp->sk_wmem_alloc), atomic_read(&sp->sk_rmem_alloc), 0, 0L, 0, sock_i_uid(sp), 0, sock_i_ino(sp), atomic_read(&sp->sk_refcnt), sp); } int udp4_seq_show(struct seq_file *seq, void *v) { if (v == SEQ_START_TOKEN) seq_printf(seq, "%-127s\n", " sl local_address rem_address st tx_queue " "rx_queue tr tm->when retrnsmt uid timeout " "inode"); else { char tmpbuf[129]; struct udp_iter_state *state = seq->private; udp4_format_sock(v, tmpbuf, state->bucket); seq_printf(seq, "%-127s\n", tmpbuf); } return 0; } /* ------------------------------------------------------------------------ */ static struct file_operations udp4_seq_fops; static struct udp_seq_afinfo udp4_seq_afinfo = { .owner = THIS_MODULE, .name = "udp", .family = AF_INET, .hashtable = udp_hash, .seq_show = udp4_seq_show, .seq_fops = &udp4_seq_fops, }; int __init udp4_proc_init(void) { return udp_proc_register(&udp4_seq_afinfo); } void udp4_proc_exit(void) { udp_proc_unregister(&udp4_seq_afinfo); } #endif /* CONFIG_PROC_FS */ EXPORT_SYMBOL(udp_disconnect); EXPORT_SYMBOL(udp_hash); EXPORT_SYMBOL(udp_hash_lock); EXPORT_SYMBOL(udp_ioctl); EXPORT_SYMBOL(udp_get_port); EXPORT_SYMBOL(udp_prot); EXPORT_SYMBOL(udp_sendmsg); EXPORT_SYMBOL(udp_lib_getsockopt); EXPORT_SYMBOL(udp_lib_setsockopt); EXPORT_SYMBOL(udp_poll); #ifdef CONFIG_PROC_FS EXPORT_SYMBOL(udp_proc_register); EXPORT_SYMBOL(udp_proc_unregister); #endif